Method for reliable control of high rotor pole switched reluctance machine

ABSTRACT

A system and method for reliable control of a high rotor pole switched reluctance machine (HRSRM) utilizing a sensorless reliable control system. The method comprising: energizing at least one of the plurality of stator phases; measuring a first current value and time taken by the first current value to reach a first peak value or preset threshold value of current; determining a self-inductance value; measuring a second current value and time taken by an adjacent un-energized stator phase to reach a second peak value of current; determining a mutual inductance value; and estimating a rotor position utilizing the self-inductance and mutual inductance values; and controlling the HRSRM based on the estimated rotor position.

RELATED APPLICATIONS

This application is continuation application of U.S. patent applicationSer. No. 17/239,566, filed Apr. 24, 2021, now U.S. patent Ser. No.11/342,872 granted May 24, 2022, and which is a continuation of U.S.patent application Ser. No. 16/841,140, filed Apr. 6, 2020, now U.S.Pat. No. 10,992,247 granted Apr. 27, 2021, and which is a continuationapplication of U.S. patent application Ser. No. 16/675,653, filed Nov.6, 2019, now U.S. Pat. No. 10,615,730 granted Apr. 7, 2020, and which isa Continuation application of U.S. patent application Ser. No.16/119,725. Filed Aug. 31, 2018, now U.S. Pat. No. 10,483,896 grantedNov. 19, 2019, and which is a Continuation application of U.S. patentapplication Ser. No. 15/800,396 filed Nov. 1, 2017, now U.S. Pat. No.10,069,449 granted Sep. 4, 2018, which is a Continuation application ofU.S. patent application Ser. No. 15/413,007 filed Jan. 23, 2017, nowU.S. Pat. No. 9,813,006 granted Nov. 7, 2017, which is a continuation inpart of U.S. patent application Ser. No. 15/016,084 filed Feb. 4, 2016,now U.S. Pat. No. 9,553,538 granted Jan. 24, 2017, and which claimspriority from the United States provisional application with Ser. No.62/111,781, was filed on Feb. 4, 2015. These applications areincorporated herein by reference as if set out in full.

BACKGROUND OF THE DISCLOSURE Technical Field of the Disclosure

The present disclosure relates in general to reliable control of highrotor pole switched reluctance machine (HRSRM), and more particularly toa system and method for eliminating the use of position sensors in HRSRMwhich improve the accuracy of rotor position estimation utilizing acombination of self-inductance and mutual-inductance values.

Description of the Related Art

A wide variety of methods have been developed to provide optimal controlstrategies for switched reluctance machines (SRMs). Compared toconventional induction and synchronous motor drive systems, SRM drivesare relatively simple in construction, offer wide speed rangecapabilities and are economic to manufacture. Further, because of theabsence of windings and permanent magnets on the rotor they areattractive for robust and harsh environment applications. In addition,the converter, which applies power to the SRM drive, often requiresfewer power devices and, therefore, is more economical and reliable.Building on these advantages, SRM drive systems provide an advancedalternative to conventional drive systems in several variable speeddrive and industrial applications. SRM drives conventionally havemultiple poles on both the stator and rotor. The stator includes phasewindings, but the rotor does not include windings or magnets.

In an SRM system, the stator generates torque on the rotor when thecurrent passing through each phase winding is switched on in apredetermined sequence. By properly positioning the firing pulsesrelative to the rotor angle, forward or reverse operations may beobtained. Usually, the desired phase current commutation is achieved byfeeding back a rotor position signal to a controller from a shaftposition sensor, e.g., an encoder or resolver. For economic reasons insmall drives and reliability reasons in larger drives and to reducesize, weight, and inertia in all such drives, it is desirable toeliminate this shaft position sensor. In order to overcome thisshortcoming, a new sensorless technique for high rotor pole switchedreluctance machine (HRSRM) has been introduced.

Compared to a conventional SRM, the HRSRM exhibits higher static torquecapabilities, which effectively addresses torque ripple and acousticnoise problems. The design parameters of the power converters aredifferent in HRSRMs vs. HRMs. This is because the HRSRM has a differentinductance profile and a higher number of strokes. Most reliabletechniques for conventional HRSRM operation utilize the self-inductanceof the phase coil to estimate position. The HRSRM has a higher number ofrotor poles for the same circumference as a conventional SRM. The highernumber of rotor poles reduces the angular travel per excitation. HRSRMhas shown an approximate increase of 83% in static torque capabilitiesas compared to a 6/4 SRM under steady state operations for the samejoule losses. However, the larger number of rotor poles leads to asmaller gap and the arc length (or angular length) between two rotorpoles is smaller. Consequently, unaligned inductance of the machine islower and the resultant the self-inductance profile for the HRSRM tendsto become flatter, which leads to unreliable position estimations. Thus,the use of self-inductance of the phase coil alone is often notsufficient to estimate the accurate rotor position in the HRSRM.

Several methods have been developed to solve the above shortcomings. Oneof the existing reliable control methods includes a technique formeasuring mutual inductance. In a first example embodiment of thistechnique, a voltage pulse is applied to the primary coil when themachine is stationary. By measuring current in the primary coil andmeasuring induced voltages in adjacent open circuited coils, mutualinductance may be determined. In another example embodiment, a voltagepulse is applied to the primary coil when the machine is stationary. Thesecondary coil is allowed to free-wheel current through the phase. Bymeasuring the time taken by the primary phase to reach a peak or presetthreshold value, the mutual inductance for the known position of a rotormay be determined. However, this technique usually does not provide anaccurate estimation of rotor position since this method only utilizesmutual inductance for the rotor position estimation.

Some other reliable control methods include a controller that implementsa model of at least one active phase representing dynamic magneticmachine characteristics. The controller determines machine controlsignals based on rotational position obtained by numerically solving themodel with measured machine operating parameters. The model may beimplemented as the sum of orthogonal functions relating active phasevoltage and current with constants derived from phase inductance toobtain the rotor angle. Yet another reliable control method includesprobing a selected diagnostic phase with a pulse injection process;measuring an actual operating characteristic of the SRM; computing aninductance based on the actual operating characteristic and correlatingthe inductance with a position to formulate an estimated position;modeling the SRM to formulate an observer-based estimated position;selecting one of the estimated positions, the observer-based estimatedposition, and a combination thereof to formulate a selected position ofthe SRM; and controlling said SRM based on said selected position and acommand. However, in most of these methods, while evaluating the machineperformance, the mutual inductances between phases are neglected,resulting in an unreliable position estimation. Further, these methodsdo not provide an accurate rotor position in a HRSRM configuration.

Therefore, there is a need for a method of reliable control of a HRSRMusing a combination of self-inductance and mutual inductance to enhancethe accuracy of rotor position estimation. The method would use onlyterminal measurements such as, voltages, currents and time and would notrequire additional hardware or memory. Further, the method would be ableto accurately estimate instantaneous rotor position in HRSRM and SRM,irrespective of motor speed or direction, and without resorting to arotor position sensor. Finally, the method would be reliable, robust andpreferably cost effective. The present embodiment accomplishes theseobjectives.

SUMMARY OF THE DISCLOSURE

To minimize the limitations found in the prior art and to minimize otherlimitations that will be apparent upon the reading of thisspecification, the Applicant provides a sensorless reliable controlsystem for a high rotor pole switched reluctance machine (HRSRM). Thepresent reliable control system utilizes electrical parameters such ascurrent and voltage to determine rotor position with high accuracythereby eliminating the required use of shaft position sensors. TheHRSRM includes a rotor and a stator with a plurality of stator phaseseach having a winding. The reliable control system includes a statorphase energizing module to excite at least one of the plurality ofstator phases. A first current and time measuring module measures afirst current value through the at least one energized stator phasetaken by the first current value to reach a first peak value of current,wherein each of the windings of the rest of the plurality of statorphases is in an open circuit state. The system further comprises aself-inductance determining module to determine the self-inductancevalue for the at least one energized stator phase utilizing the firstcurrent value and time. A first storage module stores the determinedself-inductance value and the first current value for each of theplurality of stator phases in a lookup table or alternatively theself-inductance and current values are stored in the form of ananalytical expression such as a polynomial or Fourier expression thatdescribes the inductance of each phase at each current value. A secondcurrent and time measuring module measures a second current valuethrough an adjacent un-energized stator phase and the time taken by theadjacent un-energized stator phase to reach a second peak value ofcurrent wherein the winding of the adjacent stator phase is in a shortcircuit state. A mutual-inductance determining module determines themutual inductance value between the at least one energized stator phaseand the adjacent un-energized stator phase. A second storage modulestores the mutual inductance value and the second current value for eachof the plurality of stator phases in the lookup table or in the form ofan analytical expression such as a polynomial or Fourier expression thatdescribes the inductance of each phase at each current value. A rotorposition estimation module estimates a rotor position utilizing acombination of the self-inductance and mutual inductance valuesdetermined at the self-inductance determining module and themutual-inductance determining module respectively. A control modulecontrols the HRSRM utilizing the estimated rotor position.

The preferred method provides a method for reliable control of a highrotor pole switched reluctance machine (HRSRM) utilizing the sensorlessreliable control system, the method comprising: energizing at least oneof the plurality of stator phases at a stator phase energizing module;measuring a first current value through the at least one energizedstator phase and the time taken by the first current value to reach afirst peak value of current at a first current and time measuringmodule, wherein each of the windings of the rest of the plurality ofstator phases is in an open circuit state; determining a self-inductancevalue for the at least one energized stator phase at a self-inductancedetermining module; storing the self-inductance value and the firstcurrent value for each of the plurality of stator phases at a firststorage module; measuring a second current value through an adjacentun-energized stator phase and time taken by the adjacent un-energizedstator phase to reach a second peak value of current at a second currentand time measuring module, wherein the winding of the adjacentun-energized stator phase is in a short circuit state; determining amutual inductance value between the at least one energized stator phaseand the adjacent un-energized stator phase at a mutual-inductancedetermining module; storing the mutual inductance value and the secondcurrent value for each of the plurality of stator phases at a secondstorage module; estimating a rotor position utilizing a combination ofthe stored self-inductance and mutual inductance values at a rotorposition estimation module; and controlling the HRSRM based on theestimated rotor position at a control module.

In another configuration of the preferred embodiment, the mutualinductance is determined utilizing a voltage and time values. In thisconfiguration, the reliable control system includes the stator phaseenergizing module to excite the at least one of the plurality of statorphases. The current value through the at least one energized statorphase and time taken by the current value to reach a peak value ofcurrent are measured at a current and time measuring module, whereineach of the windings of the rest of the plurality of stator phases is inan open circuit state. The self-inductance value for the at least oneenergized stator phase is determined at a self-inductance determiningmodule. The self-inductance value and the current value for each of theplurality of stator phases are stored at the first storage module. Themagnitude of voltage value across an adjacent un-energized stator phaseand time taken by a current value through the at least one energizedstator phase to reach a peak value or preset magnitude of current aremeasured at a voltage and time measuring module, wherein the winding ofthe adjacent un-energized stator phase is in an open circuit state. Themutual inductance value between the at least one energized stator phaseand the adjacent un-energized stator phase is determined at amutual-inductance determining module. In the second storage module, themutual inductance and the voltage value for each of the plurality ofstator phases are stored. The rotor position is estimated utilizing thehybrid combination of the estimated self-inductance and mutualinductance values at the rotor position estimation module. The controlmodule controls the HRSRM based on the estimated rotor position.

In one embodiment, the method for the above-mentioned configuration ofthe reliable control system comprises energizing at least one of theplurality of stator phases at a stator phase energizing module;measuring a current value through the at least one energized statorphase and time taken by the current value to reach a peak value ofcurrent at a current and time measuring module, wherein each of thewindings of the rest of the plurality of stator phases is in an opencircuit state; determining a self-inductance value for the at least oneenergized stator phase at a self-inductance determining module; storingthe self-inductance value and the current value for each of theplurality of stator phases at a first storage module; measuring avoltage value across an adjacent un-energized stator phase and timetaken by a current value through the at least one energized stator phaseto reach a peak value or preset magnitude of current at a voltage andtime measuring module, wherein the winding of the adjacent un-energizedstator phase is in the open circuit state; determining a mutualinductance value between the at least one energized stator phase and theadjacent un-energized stator phase at a mutual-inductance determiningmodule; storing the mutual inductance and the voltage value for each ofthe plurality of stator phases at a second storage module; estimating arotor position utilizing a combination of the stored self-inductance andmutual inductance values at a rotor position estimation module; andcontrolling the HRSRM based on the estimated rotor position at a controlmodule.

A first objective of the present invention is to provide a system andmethod for reliable control of a HRSRM that enhances the accuracy ofrotor position estimation by using a combination of self-inductance andmutual inductance values.

A second objective of the present invention is to provide a system andmethod for reliable control of the HRSRM that eliminates the use of arotor position sensor and the added weight and space requirementsattendant thereto.

A third objective of the present invention is to provide a method andsystem for the reliable control of the HRSRM that utilizes only terminalmeasurements such as voltages, currents and time without requiring anyadditional hardware.

Another objective of the present invention is to provide a method andsystem for reliable control of the HRSRM that is cost effective,reliable and robust.

These and other advantages and features of the present invention aredescribed with specificity so as to make the present inventionunderstandable to one of ordinary skill in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

Elements in the figures have not necessarily been drawn to scale inorder to enhance their clarity and improve the understanding of thevarious elements and embodiments of the invention. Furthermore, elementsthat are known to be common and well understood to those in the industryare not depicted in order to provide a clear view of the variousembodiments of the invention, thus the drawings are generalized in formin the interest of clarity and conciseness.

FIG. 1 illustrates a block diagram of a sensorless reliable controlsystem for a high rotor pole switched reluctance machine (HRSRM) inaccordance with one embodiment of the present invention.

FIG. 2 illustrates a flowchart of a method for reliable control of theHRSRM utilizing the sensorless reliable control system for the HRSRMshown in FIG. 1.

FIG. 3 illustrates a block diagram of another configuration of thesensorless reliable control system for the HRSRM in accordance with oneembodiment of the present invention.

FIG. 4 illustrates a flowchart of a method for the sensorless reliablecontrol system shown in FIG. 3.

FIG. 5 illustrates a converter setup to implement the sensorlessreliable control system shown in FIG. 3.

FIG. 6 illustrates a converter setup to implement the sensorlessreliable control system shown in FIG. 1.

FIG. 7 illustrates a system layout for the sensorless control of theHRSRM utilizing current measurements to estimate the rotor position inaccordance with one embodiment of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

In the following discussion that addresses a number of embodiments andapplications of the present invention, reference is made to theaccompanying drawings that form a part hereof, and in which is shown byway of illustration specific embodiments in which the invention may bepracticed. It is to be understood that other embodiments may be utilizedand changes may be made without departing from the scope of the presentinvention.

Various inventive features are described below that can each be usedindependently of one another or in combination with other features.However, any single inventive feature may not address any of theproblems discussed above, may only address one of the problems discussedabove, or may address multiple problems discussed above. Further, one ormore of the problems discussed above may not be fully addressed by anyof the features described below.

The present embodiment provides a sensorless reliable control system 10for a high rotor pole switched reluctance machine (HRSRM) 12 utilizing ahybrid combination of self-inductance and mutual inductance values asshown in FIG. 1. The HRSRM 12 includes a rotor 14 and a stator 16 with aplurality of stator phases each having a winding. The reliable controlsystem 10 comprises a stator phase energizing module 18 to excite atleast one of the plurality of stator phases. A first current and timemeasuring module 20 measures a first current value through the at leastone energized stator phase taken by the first current value to reach afirst peak value of current, wherein each of the windings of the rest ofthe plurality of stator phases is in an open circuit state. The system10 further comprises a self-inductance determining module 22 todetermine a self-inductance value for the at least one energized statorphase utilizing the first current value and time. A first storage module24 stores the determined self-inductance value and the first currentvalue for each of the plurality of stator phases in a lookup table oralternatively stored in the form of an analytical expression such as apolynomial or Fourier expression that describes the inductance of eachphase at each current value. A second current and time measuring module26 measures a second current value through an adjacent un-energizedstator phase and time taken by the adjacent un-energized stator phase toreach a second peak value of current, wherein the winding of theadjacent stator phase is in a short circuit state. The system furthercomprises a mutual-inductance determining module 28 to determine amutual inductance value between the at least one energized stator phaseand the adjacent un-energized stator phase. A second storage module 30stores the mutual inductance value and the second current value for eachof the plurality of stator phases in the lookup table or in the form ofan analytical expression (a polynomial or Fourier expression thatdescribes the inductance of each phase at each current value). A rotorposition estimation module 32 of the reliable control system 10 isdesigned to estimate a rotor position utilizing a combination of theself-inductance and mutual inductance values determined at theself-inductance determining module and the mutual-inductance determiningmodule respectively. The reliable control system 10 further comprises acontrol module 34 to control the HRSRM utilizing the estimated rotorposition.

FIG. 2 illustrates a flowchart of a method for reliable control of theHRSRM 12 utilizing the sensorless reliable control system 10. The methodis designed to control the HRSRM with high accuracy. The preferredmethod commences by providing the HRSRM with the rotor and the stator asshown in block 42. The at least one of the plurality of stator phases isenergized at the stator phase energizing module as shown in block 44.Next, the first current value through the at least one energized statorphase and the amount of time taken by the first current value to reachthe first peak value of current are determined at the first current andtime measuring module, wherein each of the windings of the rest of theplurality of stator phases is in an open circuit state as shown in block46. Then, the self-inductance value for the at least one energizedstator phase is determined at the self-inductance determining module asindicated at block 48. Thereafter, the first storage module stores theself-inductance value and the first current value for each of theplurality of stator phases in the lookup table or stores in the form ofan analytical expression as shown in block 50. The second current valuethrough the adjacent un-energized stator phase and time taken by theadjacent un-energized stator phase are measured at the second currentand time measuring module as indicated at block 52, wherein the windingof the adjacent un-energized stator phase is in a short circuit state.Next, the mutual inductance value between the at least one energizedstator phase and the adjacent un-energized stator phase are determinedat the mutual-inductance determining module as indicated at block 54.The second storage module stores the mutual inductance value and thesecond current value in the lookup table or in the form of an analyticalexpression as shown in block 56. Thereafter, the rotor position isestimated utilizing the hybrid combination of the self-inductance andmutual inductance values at the rotor position estimation module asshown in block 58. Finally, the estimated rotor position is utilized tocontrol the HRSRM at the control module as indicated at block 60.

Since one or more of the phase windings in this embodiment is switchedoff at any given time, it is possible to probe that winding with a lowlevel signal and determine its input impedance. This information,together with the knowledge of the functional relationship betweeninductance and rotor position, makes it possible to determine a highlyaccurate angular position of the rotor 14 from electrical measurementssuch as voltage and current, thereby eliminating the need for a shaftposition sensor.

Another configuration of the preferred embodiment is shown in FIG. 3. Inthis configuration, the mutual inductance is determined utilizingvoltage and time values. The reliable control system 10 includes thestator phase energizing module 18 to excite the at least one of theplurality of stator phases. A current and time measuring module 36measures the current value through the at least one energized statorphase and the time taken by the current value to reach the peak value ofcurrent, wherein each of the windings of the rest of the plurality ofstator phases is in an open circuit state. The self-inductancedetermining module 22 determines the self-inductance value for the atleast one energized stator phase. The first storage module 24 stores theself-inductance value and the current value for each of the plurality ofstator phases in the lookup table or in an analytic expression. Avoltage and time measuring module 38 measures a voltage value across anadjacent un-energized stator phase and the time taken by a current valuethrough the at least one energized stator phase to reach a peak value orpreset magnitude of current, wherein the winding of the adjacentun-energized stator phase is in an open circuit state. Themutual-inductance determining module 28 utilizes the determined voltageand time values to evaluate the mutual inductance value between the atleast one energized stator phase and the adjacent un-energized statorphase. The second storage module 30 stores the mutual inductance valueand the voltage value for each of the plurality of stator phases. Therotor position estimation module 32 estimates the rotor positionutilizing a combination of the stored self-inductance and mutualinductance values. Based on the estimated rotor position, the controlmodule 34 controls the HRSRM.

FIG. 4 illustrates a flowchart of a method for reliable control of theHRSRM utilizing the sensorless reliable control system shown in FIG. 3.The method starts by providing a HRSRM including a rotor and a statorwith a plurality of stator phases as indicated at block 62. Next, thestator phase energizing module energizes at least one of the pluralityof stator phases as shown in block 64. Thereafter, the current and timetaken by the current value to reach the peak value of current ismeasured at the current and time measuring module, wherein each of thewindings of the rest of the plurality of stator phases is in the opencircuit state as shown in block 66. The self-inductance determiningmodule determines the self-inductance value for the at least oneenergized stator phase as shown in block 68. Next, the first storagemodule stores the self-inductance value and the current value for eachof the plurality of stator phases in the lookup table or in the form ofan analytical expression as shown in block 70. As shown in block 72, thevoltage value across an adjacent un-energized stator phase and the timetaken by a current value through the at least one energized stator phaseto reach a peak value or preset magnitude of current at the voltage andtime measuring module, wherein the winding of the adjacent un-energizedstator phase is in an open circuit state. The mutual inductance valuebetween the at least one energized stator phase and the adjacentun-energized stator phase is determined at the mutual-inductancedetermining module as indicated at block 74. Next, the mutual inductanceand the voltage value for each of the plurality of stator phases arestored at the second storage module as shown in block 76. Thereafter,the rotor position is estimated utilizing the hybrid combination of thestored self-inductance and mutual inductance values at the rotorposition estimation module as indicated at block 78. Finally, theestimated rotor position is utilized to control the HRSRM at the controlmodule as shown in block 80.

During operation, any of the currently existing techniques areimplemented to measure self and mutual inductance values. In analternative embodiment, a combination of self-inductance and the backEMF from the HRSRM 12 or back EMF and mutual inductance from the HRSRM12 are used to determine the rotor position.

FIG. 5 is a diagrammatic converter setup 82 to implement the sensorlessreliable control system 10 shown in FIG. 3. This electrical circuitarrangement measures the self-inductance for phase A and themutual-inductance for open-circuited phase B.

FIG. 6 is a diagrammatic converter setup 84 to implement the sensorlessreliable control system 10 shown in FIG. 1. This electrical circuitarrangement measures the self-inductance for phase A and themutual-inductance for short-circuited phase B.

FIG. 7 is a diagrammatic system layout 86 for the sensorless reliablecontrol system 10 using current measurements to estimate the rotorposition. This electrical arrangement utilizes a gate driver circuit 88and a computer system 90 to control the electrical inputs to theplurality of stator phase windings.

The foregoing description of the preferred embodiment of the presentinvention has been presented for the purpose of illustration anddescription. It is not intended to be exhaustive or to limit theinvention to the precise form disclosed. Many modifications andvariations are possible in light of the above teachings. It is intendedthat the scope of the present invention not be limited by this detaileddescription, but by the claims and the equivalents to the claimsappended hereto.

We claim:
 1. A method for reliable control of a high rotor pole switchedreluctance machine (HRSRM) utilizing a sensorless reliable controlsystem, the method comprising: providing an HRSRM with a rotor and astator with plurality of stator phases each having a winding; energizingat least one of the plurality of stator phases at a stator phaseenergizing module; measuring a first current value through the at leastone energized stator phase and time taken by the first current value toreach a first peak value or present magnitude of current at a firstcurrent and time measuring module, wherein each of the windings of therest of the plurality of stator phases is in an open circuit state;determining a self-inductance value for the at least one energizedstator phase; measuring a second current value through an adjacentun-energized stator phase and time taken by the adjacent un-energizedstator phase to reach a second peak value of current at a second currentand time measuring module, wherein the winding of the adjacentun-energized stator phase is in a short circuit state; determining amutual inductance value between the at least one energized stator phaseand the adjacent un-energized stator phase; estimating a rotor positionutilizing a hybrid combination of the stored self-inductance and mutualinductance values at a rotor position estimation module; and controllingthe HRSRM based on the estimated rotor position at a control module. 2.The method of claim 1 wherein the self-inductance value and the firstcurrent value are stored in a look up table.
 3. The method of claim 1wherein the self-inductance value and the first current value are storedin a form of an analytical expression.
 4. The method of claim 1 whereinthe mutual-inductance value and the second current value are stored in alook up table.
 5. The method of claim 1 wherein the mutual-inductancevalue and the second current value are stored in the form of ananalytical expression.
 6. A method for reliable control of a high rotorpole switched reluctance machine (HRSRM) utilizing a sensorless reliablecontrol system, the HRSRM including a rotor and a stator with aplurality of stator phases each having a winding, the method comprisingthe steps of: energizing at least one of the plurality of stator phasesat a stator phase energizing module; measuring a current value throughthe at least one energized stator phase and time taken by the currentvalue to reach a peak value or preset magnitude of current at a currentand time measuring module, wherein each of the windings of the rest ofthe plurality of stator phases is in an open circuit state; determininga self-inductance value for the at least one energized stator phase;measuring a voltage value across an adjacent un-energized stator phaseand time taken by the current value through the at least one energizedstator phase to reach a peak value or present magnitude of current,wherein the winding of the adjacent un-energized stator phase is in anopen circuit state; determining a mutual inductance value between the atleast one energized stator phase and the adjacent un-energized statorphase; estimating a rotor position utilizing a hybrid combination of thestored self-inductance and mutual inductance values at a rotor positionestimation module; and controlling the HRSRM based on the estimatedrotor position at a control module.
 7. The method of claim 6 wherein theself-inductance value and the current value are stored in a look uptable.
 8. The method of claim 7 wherein the self-inductance value andthe current value are stored in a form of an analytical expression. 9.The method of claim 6 wherein the mutual-inductance value and thevoltage value are stored in a look up table.
 10. The method of claim 6wherein the mutual-inductance value and the voltage value are stored inthe form of an analytical expression.
 11. A sensorless reliable controlsystem for a high rotor pole switched reluctance machine (HRSRM)comprising: a stator phase energizing module to excite at least one of aplurality of stator phases each having a winding; a current and timemeasuring module to measure a first current value through the at leastone energized stator phase and time taken by the first current value toreach a pre-determined first peak value of current, wherein each of thewindings of the rest of the plurality of stator phases is in an opencircuit state; a self-inductance determining module to determine aself-inductance value for the at least one energized stator phase; acurrent and time measuring module to measure a second current valuethrough an adjacent un-energized stator phase and time taken by theadjacent un-energized stator phase to reach a second peak value ofcurrent, wherein the winding of the adjacent un-energized stator phaseis in a short circuit state; a mutual-inductance determining module todetermine a mutual inductance value between the at least one energizedstator phase and the adjacent un-energized stator phase; a rotorposition estimation module to estimate a rotor position utilizing thestored self-inductance and mutual inductance values; and a controlmodule to control the HRSRM based on the estimated rotor position. 12.The sensorless reliable control system of claim 11 wherein theself-inductance and the current values are stored in a lookup.
 13. Thesensorless reliable control system of claim 12 wherein theself-inductance and the current values are stored in the form of ananalytical expression.
 14. The sensorless reliable control system ofclaim 11 wherein the mutual-inductance and the voltage values are storedin a lookup table.
 15. The sensorless reliable control system of claim14 wherein the mutual-inductance and the voltage values are stored inthe form of an analytical expression.
 16. A sensorless reliable controlsystem for a high rotor pole switched reluctance machine (HRSRM),comprising: a stator phase energizing module to excite at least one of aplurality of stator phases each having a winding; a first current andtime measuring module to measure a first current value through the atleast one energized stator phase and time taken by the first currentvalue to reach a preset threshold of current, wherein each of thewindings of the rest of the plurality of stator phases is in an opencircuit state; a self-inductance determining module to determine aself-inductance value for the at least one energized stator phase; avoltage and time measuring module to measure a voltage value across anadjacent un-energized stator phase and time taken by a second currentvalue through the at least one energized stator phase to reach a peakvalue or present magnitude of current, wherein the winding of theadjacent un-energized stator phase is in an open circuit state; amutual-inductance determining module to determine a mutual inductancevalue between the at least one energized stator phase and the adjacentun-energized stator phase; a rotor position estimation module toestimate a rotor position utilizing the stored self-inductance andmutual inductance values; and a control module to control the HRSRMbased on the estimated rotor position.
 17. The sensorless reliablecontrol system of claim 16 wherein the self-inductance and the firstcurrent values are stored in a lookup table.
 18. The sensorless reliablecontrol system of claim 16 wherein the self-inductance and the firstcurrent values are stored in the form of an analytical expression. 19.The sensorless reliable control system of claim 16 wherein themutual-inductance and the second current values are stored in a lookuptable.
 20. The sensorless reliable control system of claim 16 whereinthe mutual-inductance and the second current values are stored in theform of an analytical expression.